Motorized surgical instrument

ABSTRACT

A surgical cutting and fastening instrument that is motorized. The instrument comprises in one embodiment a charge accumulator device, separate from a battery, that provides additional power to the motor under certain conditions. In addition, the motor may comprise multiple windings.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application claiming priorityunder 35 U.S.C. § 120 to U.S. patent application Ser. No. 15/689,738,filed Aug. 29, 2017, entitled MOTORIZED SURGICAL INSTRUMENT, now U.S.Patent Application Publication No. 2018/0085116, which is a continuationapplication claiming priority under 35 U.S.C. § 120 to U.S. patentapplication Ser. No. 14/658,524, filed Mar. 16, 2015, entitled MOTORIZEDSURGICAL INSTRUMENT, which issued as U.S. Pat. No. 10,456,133 on Oct.29, 2019, which is a continuation application claiming priority under 35U.S.C. § 120 to U.S. patent application Ser. No. 13/745,176, filed Jan.18, 2013, entitled MOTORIZED SURGICAL INSTRUMENT, which issued as U.S.Pat. No. 9,005,230 on Apr. 14, 2015, which is a continuation-in-partapplication claiming priority under 35 U.S.C. § 120 to U.S. patentapplication Ser. No. 13/021,876, filed Feb. 7, 2011, entitled MOTORIZEDSURGICAL INSTRUMENT, which issued as U.S. Pat. No. 9,028,519 on May 12,2015, which is a continuation patent application claiming priority under35 U.S.C. § 120 to U.S. patent application Ser. No. 12/235,972, filedSep. 23, 2008, entitled MOTORIZED SURGICAL INSTRUMENT, which issued asU.S. Pat. No. 9,050,083 on Jun. 9, 2015, the entire disclosures of whichare hereby incorporated by reference herein.

BACKGROUND

Surgical staplers have been used in the prior art to simultaneously makea longitudinal incision in tissue and apply lines of staples on opposingsides of the incision. Such instruments commonly include a pair ofcooperating jaw members that, if the instrument is intended forendoscopic or laparoscopic applications, are capable of passing througha cannula passageway. One of the jaw members receives a staple cartridgehaving at least two laterally spaced rows of staples. The other jawmember defines an anvil having staple-forming pockets aligned with therows of staples in the cartridge. Such instruments typically include aplurality of reciprocating wedges that, when driven distally, passthrough openings in the staple cartridge and engage drivers supportingthe staples to effect the firing of the staples toward the anvil.

An example of a surgical stapler suitable for endoscopic applications isdescribed in published U.S. Patent Application Publication No.2004/0232196, entitled, SURGICAL STAPLING INSTRUMENT HAVING SEPARATEDISTINCT CLOSING AND FIRING SYSTEMS, now U.S. Pat. No. 7,000,818, thedisclosure of which is herein incorporated by reference. In use, aclinician is able to close the jaw members of the stapler upon tissue toposition the tissue prior to firing. Once the clinician has determinedthat the jaw members are properly gripping tissue, the clinician canfire the surgical stapler, thereby severing and stapling the tissue. Thesimultaneous severing and stapling steps avoid complications that mayarise when performing such actions sequentially with different surgicaltools that respectively only sever or staple.

Motor-powered surgical cutting and fastening instruments, where a motorpowers the cutting instrument, are also known in the prior art, such asdescribed in published U.S. Patent Application Publication No.2007/0175962, entitled MOTOR-DRIVEN SURGICAL CUTTING AND FASTENINGINSTRUMENT WITH TACTILE POSITION FEEDBACK, now U.S. Pat. No. 7,422,139,which is incorporated herein by reference. In this reference, a batteryin the handle is used to electrically power the motor.

SUMMARY

In one general aspect, embodiments of the present invention are directedto motorized surgical instruments. The instruments may be endoscopicinstruments, such as linear endocutters or circular cutters, orlaparoscopic instruments. The instruments may be comprised of staplesand/or RF electrodes for fastening tissue clamped in the end effector.

Several embodiments disclosed herein are pertinent to cordlessmotor-powered instruments. In one embodiment, the instrument comprises acharge accumulator device, separate from the battery, that providesadditional power to the electric motor when needed. The chargeaccumulator device may be initially charged by the battery. Then, it maybe taken off-line until such time that the extra power from the chargeaccumulator device is needed. At that time, the charge accumulatordevice is connected in series with the battery to provide additionalpower to the motor.

In another embodiment, the motor may comprise at least two windings. Inone mode of operation, the windings are connected in series and inanother mode of the operation the windings are connected in parallel.When the windings are connected in series, the motor may have ahigh-speed low-torque output. When the windings are connected inparallel, the motor may have a low-speed high-torque output. That way,for example, the motor could exhibit both modes of operation, withoutthe instrument having to have multiple motors.

In yet another embodiment, the instrument utilizes a replaceable(possibly rechargeable) battery pack to electrically power the motor.The battery pack may comprise a plurality of battery cells. A first setof the battery cells may be connected in series in the battery pack, anda second set of battery cells may be connected in series in the batterypack, but, within the battery pack, the first set is not connected inseries to the second set. Rather, the instrument may comprise a batterycell connected in the handle, for example, that connects the first setin series with the second set when the battery pack is installed orplaced in the instrument.

These and other benefits of the present invention will be apparent fromthe description below.

FIGURES

Various embodiments of the present invention are described herein by wayof example in conjunction with the following figures, wherein:

FIGS. 1 and 2 are perspective views of a surgical cutting and fasteninginstrument according to various embodiments of the present invention;

FIGS. 3-5 are exploded views of an end effector and shaft of theinstrument according to various embodiments of the present invention;

FIG. 6 is a side view of the end effector according to variousembodiments of the present invention;

FIG. 7 is an exploded view of the handle of the instrument according tovarious embodiments of the present invention;

FIGS. 8 and 9 are partial perspective views of the handle according tovarious embodiments of the present invention;

FIG. 10 is a side view of the handle according to various embodiments ofthe present invention;

FIG. 11 is a schematic diagram of a circuit used in the instrumentaccording to various embodiments of the present invention;

FIGS. 12-14 and 17 are schematic diagrams of circuits used to power themotor of the instrument according to various embodiments of the presentinvention;

FIG. 15 is a block diagram illustrating a charge management circuitaccording to various embodiments of the present invention;

FIG. 16 is a block diagram illustrating a charger base according tovarious embodiments of the present invention;

FIG. 18 illustrates a typical power curve of a battery;

FIGS. 19A, 19B, 19C, and 20 are schematic diagrams of circuits used inthe instrument according to various embodiments of the presentinvention;

FIGS. 21 and 23 are diagrams of instruments according to variousembodiments of the present invention; and

FIGS. 22 and 24 are diagrams of battery packs according to variousembodiments of the present invention.

DESCRIPTION

FIGS. 1 and 2 depict a surgical cutting and fastening instrument 10according to various embodiments of the present invention. Theillustrated embodiment is an endoscopic instrument and, in general, theembodiments of the instrument 10 described herein are endoscopicsurgical cutting and fastening instruments. It should be noted, however,that according to other embodiments of the present invention, theinstrument may be a non-endoscopic surgical cutting and fasteninginstrument, such as a laparoscopic instrument.

The surgical instrument 10 depicted in FIGS. 1 and 2 comprises a handle6, a shaft 8, and an articulating end effector 12 pivotally connected tothe shaft 8 at an articulation pivot 14. An articulation control 16 maybe provided adjacent to the handle 6 to effect rotation of the endeffector 12 about the articulation pivot 14. In the illustratedembodiment, the end effector 12 is configured to act as an endocutterfor clamping, severing and stapling tissue, although, in otherembodiments, different types of end effectors may be used, such as endeffectors for other types of surgical devices, such as graspers,cutters, staplers, clip appliers, access devices, drug/gene therapydevices, ultrasound, RF or laser devices, etc.

The handle 6 of the instrument 10 may include a closure trigger 18 and afiring trigger 20 for actuating the end effector 12. It will beappreciated that instruments having end effectors directed to differentsurgical tasks may have different numbers or types of triggers or othersuitable controls for operating the end effector 12. The end effector 12is shown separated from the handle 6 by a preferably elongate shaft 8.In one embodiment, a clinician or operator of the instrument 10 mayarticulate the end effector 12 relative to the shaft 8 by utilizing thearticulation control 16, as described in more detail in published U.S.Patent Application Publication No. 2007/0158385, entitled SURGICALINSTRUMENT HAVING AN ARTICULATING END EFFECTOR, now U.S. Pat. No.7,670,334, which is incorporated herein by reference.

The end effector 12 includes in this example, among other things, astaple channel 22 and a pivotally translatable clamping member, such asan anvil 24, which are maintained at a spacing that assures effectivestapling and severing of tissue clamped in the end effector 12. Thehandle 6 includes a pistol grip 26 towards which a closure trigger 18 ispivotally drawn by the clinician to cause clamping or closing of theanvil 24 toward the staple channel 22 of the end effector 12 to therebyclamp tissue positioned between the anvil 24 and channel 22. The firingtrigger 20 is farther outboard of the closure trigger 18. Once theclosure trigger 18 is locked in the closure position as furtherdescribed below, the firing trigger 20 may rotate slightly toward thepistol grip 26 so that it can be reached by the operator using one hand.Then the operator may pivotally draw the firing trigger 20 toward thepistol grip 12 to cause the stapling and severing of clamped tissue inthe end effector 12. In other embodiments, different types of clampingmembers besides the anvil 24 could be used, such as, for example, anopposing jaw, etc.

It will be appreciated that the terms “proximal” and “distal” are usedherein with reference to a clinician gripping the handle 6 of aninstrument 10. Thus, the end effector 12 is distal with respect to themore proximal handle 6. It will be further appreciated that, forconvenience and clarity, spatial terms such as “vertical” and“horizontal” are used herein with respect to the drawings. However,surgical instruments are used in many orientations and positions, andthese terms are not intended to be limiting and absolute.

The closure trigger 18 may be actuated first. Once the clinician issatisfied with the positioning of the end effector 12, the clinician maydraw back the closure trigger 18 to its fully closed, locked positionproximate to the pistol grip 26. The firing trigger 20 may then beactuated. The firing trigger 20 returns to the open position (shown inFIGS. 1 and 2 ) when the clinician removes pressure, as described morefully below. A release button on the handle 6, when depressed mayrelease the locked closure trigger 18. The release button may beimplemented in various forms such as, for example, as a slide releasebutton 160 shown in FIG. 7 or any of the mechanisms described inpublished U.S. Patent Application Publication No. 2007/0175955, which isincorporated herein by reference.

FIG. 3 is an exploded view of the end effector 12 according to variousembodiments. As shown in the illustrated embodiment, the end effector 12may include, in addition to the previously mentioned channel 22 andanvil 24, a cutting instrument 32, a sled 33, a staple cartridge 34 thatis removably seated in the channel 22, and a helical screw shaft 36. Thecutting instrument 32 may be, for example, a knife. The anvil 24 may bepivotably opened and closed at a pivot point 25 connected to theproximate end of the channel 22. The anvil 24 may also include a tab 27at its proximate end that is inserted into a component of the mechanicalclosure system (described further below) to open and close the anvil 24.When the closure trigger 18 is actuated, that is, drawn in by a user ofthe instrument 10, the anvil 24 may pivot about the pivot point 25 intothe clamped or closed position. If clamping of the end effector 12 issatisfactory, the operator may actuate the firing trigger 20, which, asexplained in more detail below, causes the knife 32 and sled 33 totravel longitudinally along the channel 22, thereby cutting tissueclamped within the end effector 12. The movement of the sled 33 alongthe channel 22 causes the staples of the staple cartridge 34 to bedriven through the severed tissue and against the closed anvil 24, whichturns the staples to fasten the severed tissue. In various embodiments,the sled 33 may be an integral component of the cartridge 34. U.S. Pat.No. 6,978,921, entitled SURGICAL STAPLING INSTRUMENT INCORPORATING ANE-BEAM FIRING MECHANISM, which is incorporated herein by reference,provides more details about such two-stroke cutting and fasteninginstruments. The sled 33 may be part of the cartridge 34, such that whenthe knife 32 retracts following the cutting operation, the sled 33 doesnot retract.

It should be noted that although the embodiments of the instrument 10described herein employ an end effector 12 that staples the severedtissue, in other embodiments different techniques for fastening orsealing the severed tissue may be used. For example, end effectors thatuse RF energy or adhesives to fasten the severed tissue may also beused. U.S. Pat. No. 5,709,680 entitled ELECTROSURGICAL HEMOSTATICDEVICE, and U.S. Pat. No. 5,688,270 entitled ELECTROSURGICAL HEMOSTATICDEVICE WITH RECESSED AND/OR OFFSET ELECTRODES, which are incorporatedherein by reference, disclose an endoscopic cutting instrument that usesRF energy to seal the severed tissue. U.S. Patent ApplicationPublication No. 2007/0102453, now U.S. Pat. No. 7,673,783, and U.S.Patent Application Publication No. 2007/0102452, now U.S. Pat. No.7,607,557, which are also incorporated herein by reference, discloseendoscopic cutting instruments that use adhesives to fasten the severedtissue. Accordingly, although the description herein refers tocutting/stapling operations and the like below, it should be recognizedthat this is an exemplary embodiment and is not meant to be limiting.Other tissue-fastening techniques may also be used.

FIGS. 4 and 5 are exploded views and FIG. 6 is a side view of the endeffector 12 and shaft 8 according to various embodiments. As shown inthe illustrated embodiment, the shaft 8 may include a proximate closuretube 40 and a distal closure tube 42 pivotably linked by a pivot links44. The distal closure tube 42 includes an opening 45 into which the tab27 on the anvil 24 is inserted in order to open and close the anvil 24,as further described below. Disposed inside the closure tubes 40, 42 maybe a proximate spine tube 46. Disposed inside the proximate spine tube46 may be a main rotational (or proximate) drive shaft 48 thatcommunicates with a secondary (or distal) drive shaft 50 via a bevelgear assembly 52. The secondary drive shaft 50 is connected to a drivegear 54 that engages a proximate drive gear 56 of the helical screwshaft 36. The vertical bevel gear 52 b may sit and pivot in an opening57 in the distal end of the proximate spine tube 46. A distal spine tube58 may be used to enclose the secondary drive shaft 50 and the drivegears 54, 56. Collectively, the main drive shaft 48, the secondary driveshaft 50, and the articulation assembly (e.g., the bevel gear assembly52 a-c) are sometimes referred to herein as the “main drive shaftassembly.”

A bearing 38, positioned at a distal end of the staple channel 22,receives the helical drive screw 36, allowing the helical drive screw 36to freely rotate with respect to the channel 22. The helical screw shaft36 may interface a threaded opening (not shown) of the knife 32 suchthat rotation of the shaft 36 causes the knife 32 to translate distallyor proximately (depending on the direction of the rotation) through thestaple channel 22. Accordingly, when the main drive shaft 48 is causedto rotate by actuation of the firing trigger 20 (as explained in moredetail below), the bevel gear assembly 52 a-c causes the secondary driveshaft 50 to rotate, which in turn, because of the engagement of thedrive gears 54, 56, causes the helical screw shaft 36 to rotate, whichcauses the knife driving member 32 to travel longitudinally along thechannel 22 to cut any tissue clamped within the end effector. The sled33 may be made of, for example, plastic, and may have a sloped distalsurface. As the sled 33 traverses the channel 22, the sloped forwardsurface may push up or drive the staples in the staple cartridge throughthe clamped tissue and against the anvil 24. The anvil 24 turns thestaples, thereby stapling the severed tissue. When the knife 32 isretracted, the knife 32 and sled 33 may become disengaged, therebyleaving the sled 33 at the distal end of the channel 22.

FIGS. 7-10 illustrate an exemplary embodiment of a motor-drivenendocutter. The illustrated embodiment provides user-feedback regardingthe deployment and loading force of the cutting instrument in the endeffector. In addition, the embodiment may use power provided by the userin retracting the firing trigger 20 to power the device (a so-called“power assist” mode). As shown in the illustrated embodiment, the handle6 includes exterior lower sidepieces 59, 60 and exterior upper sidepieces 61, 62 that fit together to form, in general, the exterior of thehandle 6. A battery 64, such as a Li ion battery, may be provided in thepistol grip portion 26 of the handle 6. The battery 64 powers anelectric motor 65 disposed in an upper portion of the pistol gripportion 26 of the handle 6. According to various embodiments, a numberof battery cells connected in series may be used to power the motor 65.

The motor 65 may be a brushed driving motor having a maximum rotation ofapproximately 25,000 RPM with no load. In other embodiments, the motor65 may include a brushless motor, a cordless motor, a synchronous motor,a stepper motor, or any other suitable electric motor. The motor 64 maydrive a 90° bevel gear assembly 66 comprising a first bevel gear 68 anda second bevel gear 70. The bevel gear assembly 66 may drive a planetarygear assembly 72. The planetary gear assembly 72 may include a piniongear 74 connected to a drive shaft 76. The pinion gear 74 may drive amating ring gear 78 that drives a helical gear drum 80 via a drive shaft82. A ring 84 may be threaded on the helical gear drum 80. Thus, whenthe motor 65 rotates, the ring 84 is caused to travel along the helicalgear drum 80 by means of the interposed bevel gear assembly 66,planetary gear assembly 72, and ring gear 78.

The handle 6 may also include a run motor sensor 110 in communicationwith the firing trigger 20 to detect when the firing trigger 20 has beendrawn in (or “closed”) toward the pistol grip portion 26 of the handle 6by the operator to thereby actuate the cutting/stapling operation by theend effector 12. The sensor 110 may be a proportional sensor such as,for example, a rheostat, or variable resistor. When the firing trigger20 is drawn in, the sensor 110 detects the movement, and sends anelectrical signal indicative of the voltage (or power) to be supplied tothe motor 65. When the sensor 110 is a variable resistor or the like,the rotation of the motor 65 may be generally proportional to the amountof movement of the firing trigger 20. That is, if the operator onlydraws or closes the firing trigger 20 in a little bit, the rotation ofthe motor 65 is relatively low. When the firing trigger 20 is fullydrawn in (or in the fully closed position), the rotation of the motor 65is at its maximum. In other words, the harder the user pulls on thefiring trigger 20, the more voltage is applied to the motor 65, causinggreater rates of rotation.

The handle 6 may include a middle handle piece 104 adjacent to the upperportion of the firing trigger 20. The handle 6 also may comprise a biasspring 112 connected between posts on the middle handle piece 104 andthe firing trigger 20. The bias spring 112 may bias the firing trigger20 to its fully open position. In that way, when the operator releasesthe firing trigger 20, the bias spring 112 will pull the firing trigger20 to its open position, thereby removing actuation of the sensor 110,thereby stopping rotation of the motor 65. Moreover, by virtue of thebias spring 112, any time a user closes the firing trigger 20, the userwill experience resistance to the closing operation, thereby providingthe user with feedback as to the amount of rotation exerted by the motor65. Further, the operator could stop retracting the firing trigger 20 toremove thereby force from the sensor 100, to thereby stop the motor 65.As such, the user may stop the deployment of the end effector 12,thereby providing a measure of control of the cutting/fasteningoperation to the operator.

The distal end of the helical gear drum 80 includes a distal drive shaft120 that drives a ring gear 122, which mates with a pinion gear 124. Thepinion gear 124 is connected to the main drive shaft 48 of the maindrive shaft assembly. In that way, rotation of the motor 65 causes themain drive shaft assembly to rotate, which causes actuation of the endeffector 12, as described above.

The ring 84 threaded on the helical gear drum 80 may include a post 86that is disposed within a slot 88 of a slotted arm 90. The slotted arm90 has an opening 92 its opposite end 94 that receives a pivot pin 96that is connected between the handle exterior side pieces 59, 60. Thepivot pin 96 is also disposed through an opening 100 in the firingtrigger 20 and an opening 102 in the middle handle piece 104.

In addition, the handle 6 may include a reverse motor (or end-of-strokesensor) 130 and a stop motor (or beginning-of-stroke) sensor 142. Invarious embodiments, the reverse motor sensor 130 may be a limit switchlocated at the distal end of the helical gear drum 80 such that the ring84 threaded on the helical gear drum 80 contacts and trips the reversemotor sensor 130 when the ring 84 reaches the distal end of the helicalgear drum 80. The reverse motor sensor 130, when activated, sends asignal to the motor 65 to reverse its rotation direction, therebywithdrawing the knife 32 of the end effector 12 following the cuttingoperation. The stop motor sensor 142 may be, for example, a normallyclosed limit switch. In various embodiments, it may be located at theproximate end of the helical gear drum 80 so that the ring 84 trips theswitch 142 when the ring 84 reaches the proximate end of the helicalgear drum 80.

In operation, when an operator of the instrument 10 pulls back thefiring trigger 20, the sensor 110 detects the deployment of the firingtrigger 20 and sends a signal to the motor 65 to cause forward rotationof the motor 65 at, for example, a rate proportional to how hard theoperator pulls back the firing trigger 20. The forward rotation of themotor 65 in turn causes the ring gear 78 at the distal end of theplanetary gear assembly 72 to rotate, thereby causing the helical geardrum 80 to rotate, causing the ring 84 threaded on the helical gear drum80 to travel distally along the helical gear drum 80. The rotation ofthe helical gear drum 80 also drives the main drive shaft assembly asdescribed above, which in turn causes deployment of the knife 32 in theend effector 12. That is, the knife 32 and sled 33 are caused totraverse the channel 22 longitudinally, thereby cutting tissue clampedin the end effector 12. Also, the stapling operation of the end effector12 is caused to happen in embodiments where a stapling-type end effectoris used.

By the time the cutting/stapling operation of the end effector 12 iscomplete, the ring 84 on the helical gear drum 80 will have reached thedistal end of the helical gear drum 80, thereby causing the reversemotor sensor 130 to be tripped, which sends a signal to the motor 65 tocause the motor 65 to reverse its rotation. This in turn causes theknife 32 to retract, and also causes the ring 84 on the helical geardrum 80 to move back to the proximate end of the helical gear drum 80.

The middle handle piece 104 includes a backside shoulder 106 thatengages the slotted arm 90 as best shown in FIGS. 8 and 9 . The middlehandle piece 104 also has a forward motion stop 107 that engages thefiring trigger 20. The movement of the slotted arm 90 is controlled, asexplained above, by rotation of the motor 65. When the slotted arm 90rotates CCW as the ring 84 travels from the proximate end of the helicalgear drum 80 to the distal end, the middle handle piece 104 will be freeto rotate CCW. Thus, as the user draws in the firing trigger 20, thefiring trigger 20 will engage the forward motion stop 107 of the middlehandle piece 104, causing the middle handle piece 104 to rotate CCW. Dueto the backside shoulder 106 engaging the slotted arm 90, however, themiddle handle piece 104 will only be able to rotate CCW as far as theslotted arm 90 permits. In that way, if the motor 65 should stoprotating for some reason, the slotted arm 90 will stop rotating, and theuser will not be able to further draw in the firing trigger 20 becausethe middle handle piece 104 will not be free to rotate CCW due to theslotted arm 90.

Components of an exemplary closure system for closing (or clamping) theanvil 24 of the end effector 12 by retracting the closure trigger 18 arealso shown in FIGS. 7-10 . In the illustrated embodiment, the closuresystem includes a yoke 250 connected to the closure trigger 18 by a pin251 that is inserted through aligned openings in both the closuretrigger 18 and the yoke 250. A pivot pin 252, about which the closuretrigger 18 pivots, is inserted through another opening in the closuretrigger 18 which is offset from where the pin 251 is inserted throughthe closure trigger 18. Thus, retraction of the closure trigger 18causes the upper part of the closure trigger 18, to which the yoke 250is attached via the pin 251, to rotate CCW. The distal end of the yoke250 is connected, via a pin 254, to a first closure bracket 256. Thefirst closure bracket 256 connects to a second closure bracket 258.Collectively, the closure brackets 256, 258 define an opening in whichthe proximate end of the proximate closure tube 40 (see FIG. 4 ) isseated and held such that longitudinal movement of the closure brackets256, 258 causes longitudinal motion by the proximate closure tube 40.The instrument 10 also includes a closure rod 260 disposed inside theproximate closure tube 40. The closure rod 260 may include a window 261into which a post 263 on one of the handle exterior pieces, such asexterior lower sidepiece 59 in the illustrated embodiment, is disposedto fixedly connect the closure rod 260 to the handle 6. In that way, theproximate closure tube 40 is capable of moving longitudinally relativeto the closure rod 260. The closure rod 260 may also include a distalcollar 267 that fits into a cavity 269 in proximate spine tube 46 and isretained therein by a cap 271 (see FIG. 4 ).

In operation, when the yoke 250 rotates due to retraction of the closuretrigger 18, the closure brackets 256, 258 cause the proximate closuretube 40 to move distally (i.e., away from the handle end of theinstrument 10), which causes the distal closure tube 42 to movedistally, which causes the anvil 24 to rotate about the pivot point 25into the clamped or closed position. When the closure trigger 18 isunlocked from the locked position, the proximate closure tube 40 iscaused to slide proximately, which causes the distal closure tube 42 toslide proximately, which, by virtue of the tab 27 being inserted in thewindow 45 of the distal closure tube 42, causes the anvil 24 to pivotabout the pivot point 25 into the open or unclamped position. In thatway, by retracting and locking the closure trigger 18, an operator mayclamp tissue between the anvil 24 and channel 22, and may unclamp thetissue following the cutting/stapling operation by unlocking the closuretrigger 20 from the locked position.

Additional configurations for motorized surgical instruments aredisclosed in U.S. Patent Application Publication No. 2007/0175962,entitled MOTOR-DRIVEN SURGICAL CUTTING AND FASTENING INSTRUMENT WITHTACTILE POSITION FEEDBACK, now U.S. Pat. No. 7,422,139, which isincorporated herein by reference in its entirety.

FIG. 11 is a schematic diagram of the motor control circuit according tovarious embodiments of the present invention. In various embodiments,the motor control circuit may include one of more integrated circuits(ICs), such as, for example, a processor, memory, microcontroller, timecircuits, etc. In other embodiments, the motor control circuit may notcomprise any ICs. Such a non-IC motor control circuit may beadvantageous because it is often difficult, complicated, and expensiveto sterilize a surgical instrument including ICs.

When an operator initially pulls in the firing trigger 20 after lockingthe closure trigger 18, the sensor 110 is activated (or closed, wherethe sensor 110 is a switch), allowing current to flow therethrough. Ifthe normally open reverse motor sensor switch 130 is open (meaning theend of the end effector stroke has not been reached), current will flowto a single pole, double throw relay 132. When the reverse motor sensorswitch 130 is not closed, a coil 134 of the relay 132 will not beenergized, so the relay 132 will be in its de-energized state.

As shown in FIG. 11 , the circuit may also include a resistive element144 and a switch 146 connected in parallel, with the paralleled elementsconnected in series with the relay 132. The resistive element 144 andthe switch 146 are also connected to the power source 64. The switch 146may be controlled by a control circuit 148 that is responsive to thecutting instrument position sensor 150. According to variousembodiments, the control circuit 148 may open the switch 146 when thecutting instrument 32 is (i) very near to the beginning of its strokeand (ii) very near to the end of its stroke. For example, the controlcircuit may open the switch when the cutting instrument 32 is (i) 0.001inches from the beginning point of its stroke and (ii) 0.001 inches fromthe end of its stroke, as determined by the cutting instrument positionsensor 150. With the switch 146 open, current flows through theresistive element 144, and then through the relay 132, the relay 138,the run motor sensor switch 110, to the motor 65. Current flowingthrough the resistive element 144 reduces the magnitude of the currentdelivered to the motor 65, thereby reducing the power delivered by themotor 65. Thus, when the cutting instrument 32 is (i) very near to thebeginning of its stroke or (ii) very near to the end of its stroke, thepower delivered by the motor 65 is reduced. Conversely, once the cuttinginstrument 32 moves sufficiently far from its beginning point or end ofstroke point, the control circuit 148 may close the switch 146, therebyshorting the resistive element 144, thereby increasing the current tothe motor 65, thereby increasing the power delivered by the motor.

According to various embodiments, the electrical circuit furtherincludes lockout sensor switches 136 a-d collectively defining aninterlock circuit 137 through which current from the relay 132, whende-energized, passes in order for electrical operation of the motor 65to be initiated. Each lockout sensor switch 136 a-d may be configured tomaintain an open (i.e., non-conductive) switch state or a closed (i.e.,conductive) switch state responsive to the presence or absence,respectively, of a corresponding condition. Any of the correspondingconditions, if present when the instrument 10 is fired, may result in anunsatisfactory cutting and stapling operation and/or damage to theinstrument 10. Conditions to which the lockout sensor switches 136 a-dmay respond include, for example, (a) the absence of the staplecartridge 34 in the channel 22, (b) the presence of a spent (e.g.,previously fired) staple cartridge 34 in the channel 22, and (c) an open(or otherwise insufficiently closed) position of the anvil 24 withrespect to the channel 22. Other conditions to which the lockout sensorswitches 136 a-d may respond, such as component wear, may be inferredbased upon an accumulated number of firing operations produced by theinstrument 10. Accordingly, in various embodiments, if any of theseconditions exists, the corresponding lockout sensor switches 136 a-dmaintain an open switch state, thus preventing passage of the currentnecessary to initiate operation of the motor 65. Passage of current bythe lockout sensors 136 a-d is allowed, in various embodiments, onlyafter all of the conditions have been remedied. It will be appreciatedthat the above-described conditions are provided by way of example only,and that additional lockout sensor switches for responding to otherconditions detrimental to operation of the instrument 10 may beprovided. It will similarly be appreciated that for embodiments in whichone or more of the above-described conditions may not exist or are of noconcern, the number of lockout sensor switches may be fewer than thatdepicted.

As shown in FIG. 11 , the lockout sensor switch 136 a may be implementedusing a normally open switch configuration such that a closed switchstate is maintained when the staple cartridge 34 is in a positioncorresponding to its proper receipt by the channel 22. When the staplecartridge 34 is not installed in the channel 22, or is installedimproperly (e.g., misaligned), the lockout sensor switch 136 a maintainsan open switch state. Lockout sensor switch 136 b may be implementedusing a normally open switch configuration such that a closed switchstate is maintained only when an unspent staple cartridge 34 (i.e., astaple cartridge 34 having a sled 33 in the unfired position) is presentin the channel 22. The presence of a spent staple cartridge 34 in thechannel 22 causes the lockout sensor switch 136 b to maintain an openswitch state. Lockout sensor switch 136 c may be implemented using anormally open switch configuration such that a closed switch state ismaintained when the anvil 24 is in a closed position with respect to thechannel 22. The lockout sensor switch 136 c may be controlled inaccordance with a time delay feature wherein a closed switch state ismaintained only after the anvil 24 is in the closed position for apre-determined period of time.

Lockout sensor switch 136 d may be implemented using a normally closedswitch configuration such that a closed switch state is maintained onlywhen an accumulated number of firings produced by the instrument 10 isless than a pre-determined number. The lockout sensor switch 136 d maybe in communication with a counter 139 configured for maintaining acount representative of the accumulated number of firing operationsperformed by the instrument 10, comparing the count to thepre-determined number, and controlling the switch state of the lockoutsensor switch 136 d based upon the comparison. Although shown separatelyin FIG. 11 , it will be appreciated that counter 139 may be integralwith the lockout sensor switch 136 d so as to form a common device.Preferably, the counter 139 is implemented as an electronic devicehaving an input for incrementing the maintained count based upon thetransition of a discrete electrical signal provided thereto. It will beappreciated that a mechanical counter configured for maintaining thecount based upon a mechanical input (e.g., retraction of the firingtrigger 20) may be used instead. When implemented as an electronicdevice, any discrete signal present in the electrical circuit thattransitions once for each firing operation may be utilized for thecounter 139 input. As shown in FIG. 11 , for example, the discreteelectrical signal resulting from actuation of the end-of-stroke sensor130 may be utilized. The counter 139 may control the switch state oflockout sensor switch 136 d such that a closed switch state ismaintained when the maintained count is less than a pre-determinednumber stored within the counter 139. When the maintained count is equalto the pre-determined number, the counter 139 causes the lockout sensorswitch 136 d to maintain an open switch state, thus preventing thepassage of current therethrough. It will be appreciated that thepre-determined number stored by the counter 139 may be selectivelyadjusted as required. According to various embodiments, the counter 304may be in communication with an external display (not shown), such as anLCD display, integral to the instrument 10 for indicating to a usereither the maintained count or the difference between the pre-determinednumber and the maintained count.

According to various embodiments, the interlock circuit 137 may compriseone or more indicators visible to the user of the instrument 10 fordisplaying a status of at least one of the lockout sensor switches 136a-d. More details regarding such indicators may be found in publishedU.S. Patent Application Publication No. 2007/0175956, entitledELECTRONIC LOCKOUTS AND SURGICAL INSTRUMENT INCLUDING SAME, now U.S.Pat. No. 7,644,848, which is incorporated herein by reference in itsentirety. This application also includes example mounting arrangementsand configurations for the lockout sensor switches 136 a-d.

In the illustrated embodiment, when the lockout sensor switches 136 a-dcollectively maintain a closed switch state, a single pole, single throwrelay 138 is energized. When the relay 138 is energized, current flowsthrough the relay 138, through the run motor switch sensor 110, and tothe motor 65 via a double pole, double throw relay 140, thereby poweringthe motor 65, allowing it to rotate in the forward direction. Accordingto various embodiments, because the output of the relay 138, onceenergized, maintains the relay 138 in an energized state until relay 132is energized, the interlock circuit 137 will not function to preventoperation of the motor 165 once initiated, even if one or more of theinterlock sensor switches 136 a-d subsequently maintains an open switchstate. In other embodiments, however, it may be necessary or otherwisedesirable to connect the interlock circuit 137 and the relay 138 suchthat one or more the lockout sensor switches 136 a-d must maintain aclosed switch state in order to sustain operation of the motor 165 onceinitiated.

Rotation of the motor in the forward direction causes the ring 84 tomove distally and thereby de-actuate the stop motor sensor switch 142 invarious embodiments. Because the switch 142 is normally closed, asolenoid 141 connected to the switch 142 may be energized. The solenoid141 may be a conventional push-type solenoid that, when energized,causes a plunger (not shown) to be axially extended. Extension of theplunger may operate to retain the closure trigger 18 in the retractedposition, thus preventing the anvil 24 from opening while a firingoperation is in progress (i.e., while the switch 142 is not actuated).Upon deenergization of the solenoid 141, the plunger is retracted suchthat manual release of the closure trigger 18 is possible.

When the end effector 12 reaches the end of its stroke, the reversemotor sensor 130 will be activated, thereby closing the switch 130 andenergizing the relay 132. This causes the relay 132 to assume itsenergized state (not shown in FIG. 11 ), which causes current to bypassthe interlock circuit 137 and run motor sensor switch 110, and insteadcauses current to flow to both the normally-closed double pole, doublethrow relay 140 and back to the motor 65, but in a manner, via the relay140, that causes the motor 65 to reverse its rotational direction.Because the stop motor sensor switch 142 is normally closed, currentwill flow back to the relay 132 to keep it energized until the switch142 opens. When the knife 32 is fully retracted, the stop motor sensorswitch 142 is activated, causing the switch 142 to open, therebyremoving power from the motor 65, and de-energizing the solenoid 141.

In other embodiments, other alternatives may be used to limit thecurrent supplied to the motor 65 during certain time periods during thecutting stroke cycle. Other embodiments are described in U.S. patentapplication Ser. No. 12/235,782, now U.S. Pat. No. 8,210,411, which isincorporated herein by reference in its entirety.

In some instances, it may be advantageous to provide a momentaryincrease in current to the motor 65 to increase the output torque. FIG.19A shows an embodiment of a circuit for providing a momentary increaseto the motor 65 according to various embodiments. The circuit is similarto that shown in FIG. 11 , except that the circuit of FIG. 19Aadditionally includes a charge accumulator device 1000 connected to thepower source 64. The charge accumulator device 1000 may be any devicethat can store charge, such as a capacitor. For example, the chargeaccumulator device 1000 may comprise an ultracapacitor (sometimes calleda supercapacitor). When the motor 65 is first turned on, such as whenthe switch 110 is closed due to retraction of the firing trigger 20, theswitch S1 may be closed so that the battery 64 can power the motor 65 asdescribed above. In addition, the switch S3 may also be closed for onlya brief period of time (“the charging period”) to charge the chargeaccumulator device 1000 via the resistor R. For example, according tovarious embodiments, the switch S3 may be closed for one to ten RC timeconstants, where R is the resistance of the resistor R and C is thecapacitance of the charge accumulator device 1000.

The charge in the charge accumulator device 1000 may remain unusedduring normal operating conditions, but if there comes a time in theprocedure where the clinician needs additional output torque from themotor 65, the charge accumulator device 1000 could be put in series withthe battery 64. This could be done, for example, by opening switch S1and closing switch S2 (with S3 remaining open following the chargingperiod). With switch S2 closed, the charge accumulator device 1000 wouldbe connected in series with the battery 64, thereby supplying additionalcurrent to the motor 65.

The condition requiring the charge accumulator device 1000 may bedetected in numerous ways. For example, there may be a variable resistoror spring connected to the firing trigger 20. When the firing trigger isretracted beyond a certain point or with a force above a thresholdlevel, the charge accumulator device 1000 may be connected in series tothe battery 64. Additionally or alternatively, the handle 6 may comprisean external switch (not shown) that the clinician could activate toconnect the charge accumulator device 1000 in series with battery 64.

The charge accumulator device 1000 could be used with or without thecurrent limiting devices described above in connection with FIG. 11 .

FIG. 19B shows an embodiment of an alternative circuit to that shown inFIG. 19A for providing a momentary increase in current to the motor 65according to various embodiments. In some arrangements of the circuit,the battery 64 alone may power the motor 65. For example, switch Sb canbe closed, in combination with switch 110 being closed, to provide powerfrom only the battery 64 to the motor 65. The remaining switches Sa, Sc,Sd, and Se can remain open. As another example, switches Sd and Se canbe closed, in combination with switch 110 being closed, to provide powerfrom only the battery 64 to the motor 65. The remaining switches Sa, Sc,and Sb can remain open. As yet another example, switches Sb, Sd, and Secan be closed, in combination with switch 110 being closed, to providepower from only the battery 64 to the motor 65. The remaining switchesSa and Sc can remain open. In some arrangements of the circuit, thebattery 64 may charge the charge accumulator device 1000 withoutpowering the motor 65. For example, switches Sc and Sd can be closed tocharge the charge accumulator device 1000 without powering the motor 65.The remaining switches Sa, Sb, and Se can remain open. In somearrangements of the circuit, the battery 64 can simultaneously power themotor 65 and charge the charge accumulator device 1000. For example,switches Sc, Sd, and Se can be closed, in combination with switch 110being closed, to simultaneously charge the charge accumulator device1000 and power the motor 65. The remaining switches Sa and Sb can remainopen. As another example, switches Sb, Sc, and Se can be closed, incombination with switch 110 being closed, to simultaneously charge thecharge accumulator device 1000 and power the motor 65. The remainingswitches Sa and Sd can remain open. As another example, switches Sb, Sc,Sd, and Se can be closed, in combination with switch 110 being closed,to simultaneously charge the charge accumulator device 1000 and powerthe motor 65. The remaining switch Sa can remain open. In somearrangements of the circuit, the battery 64 and the charged chargeaccumulator device 1000 can be coupled in series to power the motor 65.For example, switches Sa and Se can be closed, in combination withswitch 110 being closed, to couple the battery 64 and charge accumulatordevice 1000 in series with the motor 65. The remaining switches Sb, Sc,and Sd can remain open.

FIG. 19C shows an embodiment of an alternative circuit to the circuitsshown in FIGS. 19A and 19B for providing a momentary increase in currentto the motor 65 according to various embodiments. In some arrangementsof the circuit, the battery 64 alone may power the motor 65. Forexample, switches Sd and Se can be closed, in combination with switch110 being closed, to provide power from only the battery 64 to the motor65. The remaining switches Sa and Sc can remain open. In somearrangements of the circuit, the battery 64 may charge the chargeaccumulator device 1000 without powering the motor 65. For example,switches Sc and Sd can be closed to charge the charge accumulator device1000 without powering the motor 65. The remaining switches Sa and Se canremain open. In some arrangements of the circuit, the battery 64 cansimultaneously power the motor 65 and charge the charge accumulatordevice 1000. For example, switches Sc, Sd, and Se can be closed, incombination with switch 110 being closed, to simultaneously charge thecharge accumulator device 1000 and power the motor 65. The remainingswitch Sa can remain open. In some arrangements of the circuit, thebattery 64 and the charged charge accumulator device 1000 can be coupledin series to power the motor 65. For example, switches Sa and Se can beclosed, in combination with switch 110 being closed, to couple thebattery 64 and charge accumulator device 1000 in series with the motor65. The remaining switches Sc and Sd can remain open.

At some times during use of the instrument 10, it may be advantageous tohave the motor 65 run at high speed but relatively low torque output. Atother times, it may be desirable to have the motor 65 have a high torqueoutput but at low speeds. According to various embodiments, thisfunctionality may be accomplished with a motor 65 having multiple (e.g.,two or more) windings, as shown in FIG. 20 . In the illustratedembodiment, the motor has two windings. A first winding 1200 may havewinding halves (or portions) 1201 and 1202. A second winding 1204 mayhave winding halves (or portions) 1206 and 1208. The motor 65 in thisexample may be a 6 or 8 lead motor with a bipolar driving circuit 1210(see FIGS. 11 and 12 , for example). When the high-speed low-torque modeis desired, the two sets of winding may be connected in series. In thismode, as shown in FIG. 20 , switches S1 and S4 are closed, and switchesS2, S3, S5, and S6 are open. When the low-speed high-torque mode isdesired, the two sets of windings may be connected in parallel. In thismode, switches S1 and S4 are open, and switches S2, S3, S5, and S6 areclosed. The ability to transition between the two modes effectivelycreates a two-speed transmission with no additional moving parts. Italso allows the same motor to generate both high speeds and high torqueoutputs, albeit not at the same time. An advantage of this configurationis that it avoids using multiple motors. In addition, it may be possibleto eliminate some gearing because the motor 65 can generate extra torquewhen in the parallel mode and extra speed when in the series mode. Inaddition, additional windings could be employed such that a greaternumber of operating modes may be realized. For example, there could bewindings for multiple combinations of series and parallel windingconnections. Also, some windings may be used for sensing motorconditions, etc.

According to various embodiments, the handle 6 may comprise an externalmotor mode selection switch 1220, as shown in FIG. 21 . By using theswitch 1220, the operator of the instrument 10 could select with themotor 65 is in the high-speed low-torque mode or in the low-speedhigh-torque mode. Other switching circuits could also be used to togglethe motor 65 between the operating modes, such as switching circuitsthat automatically switch the motor mode based on sensor inputs.

In a motorized surgical instrument, such as one of the motorizedendoscopic instruments described above or in a motorized circular cutterinstrument, the motor may be powered by a number of battery cellsconnected in series. Further, it may be desirable in certaincircumstances to power the motor with some fraction of the total numberof battery cells. For example, as shown in FIG. 12 , the motor 65 may bepowered by a power pack 299 comprising six (6) battery cells 310connected in series. The battery cells 310 may be, for example, 3-voltlithium battery cells, such as CR 123A battery cells, although in otherembodiments, different types of battery cells could be used (includingbattery cells with different voltage levels and/or differentchemistries). If six 3-volt battery cells 310 were connected in seriesto power the motor 65, the total voltage available to power the motor 65would be 18 volts. The battery cells 310 may comprise rechargeable ornon-rechargeable battery cells.

In such an embodiment, under the heaviest loads, the input voltage tothe motor 65 may sag to about nine to ten volts. At this operatingcondition, the power pack 299 is delivering maximum power to the motor65. Accordingly, as shown in FIG. 12 , the circuit may include a switch312 that selectively allows the motor 65 to be powered by either (1) allof the battery cells 310 or (2) a fraction of the battery cells 310. Asshown in FIG. 12 , by proper selection, the switch 312 may allow themotor 65 to be powered by all six battery cells or four of the batterycells. That way, the switch 312 could be used to power the motor 65 witheither 18 volts (when using all six battery cells 310) or 12 volts (suchusing four of the second battery cells). In various embodiments, thedesign choice for the number of battery cells in the fraction that isused to power the motor 65 may be based on the voltage required by themotor 65 when operating at maximum output for the heaviest loads.

The switch 312 may be, for example, an electromechanical switch, such asa micro switch. In other embodiments, the switch 312 may be implementedwith a solid-state switch, such as transistor. A second switch 314, suchas a push button switch, may be used to control whether power is appliedto the motor 65 at all. Also, a forward/reverse switch 316 may be usedto control whether the motor 65 rotates in the forward direction or thereverse direction. The forward/reverse switch 316 may be implementedwith a double pole—double throw switch, such as the relay 140 shown inFIG. 11 .

In operation, the user of the instrument 10 could select the desiredpower level by using some sort of switch control, such as aposition-dependent switch (not shown), such as a toggle switch, amechanical lever switch, or a cam, which controls the position of theswitch 312. Then the user may activate the second switch 314 to connectthe selected battery cells 310 to the motor 65. In addition, the circuitshown in FIG. 12 could be used to power the motor of other types ofmotorized surgical instruments, such as circular cutters and/orlaparoscopic instruments. More details regarding circular cutters may befound in published U.S. Patent Application Publication Nos.2006/0047307, now U.S. Pat. No. 8,317,074 and 2007/0262116, now U.S.Pat. No. 7,500,979, which are incorporated herein by reference.

In other embodiments, as shown in FIG. 13 , a primary power source 340,such as a battery cell, such as a CR2 or CR123A battery cell, may beused to charge a number of secondary accumulator devices 342. Theprimary power source 340 may comprise one or a number ofseries-connected battery cells, which are preferably replaceable in theillustrated embodiment. The secondary accumulator devices 342 maycomprise, for example, rechargeable battery cells and/or supercapacitors(also known as “ultracapacitors” or “electrochemical double layercapacitors” (EDLC)). Supercapacitors are electrochemical capacitors thathave an unusually high energy density when compared to commonelectrolytic capacitors, typically on the order of thousands of timesgreater than a high-capacity electrolytic capacitor.

The primary power source 340 may charge the secondary accumulatordevices 342. Once sufficiently charged, the primary power source 340 maybe removed and the secondary accumulator devices 342 may be used topower the motor 65 during a procedure or operation. The accumulatingdevices 342 may take about fifteen to thirty minutes to charge invarious circumstances. Supercapacitors have the characteristic they cancharge and discharge extremely rapidly in comparison to conventionalbatteries. In addition, whereas batteries are good for only a limitednumber of charge/discharge cycles, supercapacitors can often becharged/discharged repeatedly, sometimes for tens of millions of cycles.For embodiments using supercapacitors as the secondary accumulatordevices 342, the supercapacitors may comprise carbon nanotubes,conductive polymers (e.g., polyacenes), or carbon aerogels.

As shown in FIG. 14 , a charge management circuit 344 could be employedto determine when the secondary accumulator devices 342 are sufficientlycharged. The charge management circuit 344 may include an indicator,such as one or more LEDs, an LCD display, etc., that is activated toalert a user of the instrument 10 when the secondary accumulator devices342 are sufficiently charged.

The primary power source 340, the secondary accumulator devices 342, andthe charge management circuit 344 may be part of a power pack in thepistol grip portion 26 of the handle 6 of the instrument 10, or inanother part of the instrument 10. The power pack may be removable fromthe pistol grip portion 26, in which case, when the instrument 10 is tobe used for surgery, the power pack may be inserted aseptically into thepistol grip portion 26 (or other position in the instrument according toother embodiments) by, for example, a circulating nurse assisting in thesurgery. After insertion of the power pack, the nurse could put thereplaceable primary power source 340 in the power pack to charge up thesecondary accumulator devices 342 a certain time period prior to use ofthe instrument 10, such as thirty minutes. When the secondaryaccumulator devices 342 are charged, the charge management circuit 344may indicate that the power pack is ready for use. At this point, thereplaceable primary power source 340 may be removed. During theoperation, the user of the instrument 10 may then activate the motor 65,such as by activating the switch 314, whereby the secondary accumulatordevices 342 power the motor 65. Thus, instead of having a number ofdisposable batteries to power the motor 65, one disposable battery (asthe primary power source 340) could be used in such an embodiment, andthe secondary accumulator devices 342 could be reusable. In alternativeembodiments, however, it should be noted that the secondary accumulatordevices 342 could be non-rechargeable and/or non-reusable. The secondaryaccumulators 342 may be used with the cell selection switch 312described above in connection with FIG. 12 .

The charge management circuit 344 may also include indicators (e.g.,LEDs or LCD display) that indicate how much charge remains in thesecondary accumulator devices 342. That way, the surgeon (or other userof the instrument 10) can see how much charge remains through the courseof the procedure involving the instrument 10.

The charge management circuit 344, as shown in FIG. 15 , may comprise acharge meter 345 for measuring the charge across the secondaryaccumulators 342. The charge management circuit 344 also may comprise anon-volatile memory 346, such as flash or ROM memory, and one or moreprocessors 348. The processor(s) 348 may be connected to the memory 346to control the memory. In addition, the processor(s) 348 may beconnected to the charge meter 345 to read the readings of and otherwisecontrol the charge meter 345. Additionally, the processor(s) 348 maycontrol the LEDs or other output devices of the charge managementcircuit 344. The processor(s) 348 can store parameters of the instrument10 in the memory 346. The parameters may include operating parameters ofthe instrument that are sensed by various sensors that may be installedor employed in the instrument 10, such as, for example, the number offirings, the levels of forces involved, the distance of the compressiongap between the opposing jaws of the end effector 12, the amount ofarticulation, etc. Additionally, the parameters stored in the memory 346may comprise ID values for various components of the instrument 10 thatthe charge management circuit 344 may read and store. The componentshaving such IDs may be replaceable components, such as the staplecartridge 34. The IDs may be for example, RFIDs that the chargemanagement circuit 344 reads via a RFID transponder 350. The RFIDtransponder 350 may read RFIDs from components of the instrument, suchas the staple cartridge 34, that include RFID tags. The ID values may beread, stored in the memory 346, and compared by the processor 348 to alist of acceptable ID values stored in the memory 346 or another storeassociated with the charge management circuit, to determine, forexample, if the removable/replaceable component associated with the readID value is authentic and/or proper. According to various embodiments,if the processor 348 determines that the removable/replaceable componentassociated with the read ID value is not authentic, the chargemanagement circuit 344 may prevent use of the power pack by theinstrument 10, such as by opening a switch (not shown) that wouldprevent power from the power pack being delivered to the motor 65.According to various embodiments, various parameters that the processor348 may evaluate to determine whether the component is authentic and/orproper include: date code; component model/type; manufacturer; regionalinformation; and previous error codes.

The charge management circuit 344 may also comprise an i/o interface 352for communicating with another device, such as described below. Thatway, the parameters stored in the memory 346 may be downloaded toanother device. The i/o interface 352 may be, for example, a wired orwireless interface.

As mentioned before, the power pack may comprise the secondaryaccumulators 342, the charge management circuit 344, and/or the f/rswitch 316. According to various embodiments, as shown in FIG. 16 , thepower pack 299 could be connected to a charger base 362, which may,among other things, charge the secondary accumulators 342 in the powerpack. The charger base 362 could be connected to the power pack 299 byconnecting aseptically the charger base 362 to the power pack 299 whilethe power pack is installed in the instrument 10. In other embodimentswhere the power pack is removable, the charger base 362 could beconnected to the power pack 299 by removing the power pack 299 from theinstrument 10 and connecting it to the charger base 362. For suchembodiments, after the charger base 362 sufficiently charges thesecondary accumulators 342, the power pack 299 may be asepticallyinstalled in the instrument 10.

As shown in FIG. 16 , the charger base 362 may comprise a power source364 for charging the secondary accumulators 342. The power source 364 ofthe charger base 362 may be, for example, a battery (or a number ofseries-connected batteries), or an AC/DC converter that converters ACpower, such as from electrical power mains, to DC, or any other suitablepower source for charging the secondary accumulators 342. The chargerbase 362 may also comprise indicator devices, such as LEDs, a LCDdisplay, etc., to show the charge status of the secondary accumulators342.

In addition, as shown in FIG. 16 , the charger base 362 may comprise oneor more processors 366, one or more memory units 368, and i/o interfaces370, 372. Through the first i/o interface 370, the charger base 362 maycommunicate with the power pack 299 (via the power pack's i/o interface352). That way, for example, data stored in the memory 346 of the powerpack 299 may be downloaded to the memory 368 of the charger base 362. Inthat way, the processor 366 can evaluate the ID values for theremovable/replaceable components, downloaded from the charge managementcircuit 344, to determine the authenticity and suitability of thecomponents. The operating parameters downloaded from the chargemanagement circuit 344 may also stored in the memory 368, and then maythen be downloaded to another computer device via the second i/ointerface 372 for evaluation and analysis, such as by the hospitalsystem in which the operation involving the instrument 10 is performed,by the office of the surgeon, by the distributor of the instrument, bythe manufacturer of the instrument, etc.

The charger base 362 may also comprise a charge meter 374 for measuringthe charge across the secondary accumulators 342. The charge meter 374may be in communication with the processor(s) 366, so that theprocessor(s) 366 can determine in real-time the suitability of the powerpack 299 for use to ensure high performance.

In another embodiment, as shown in FIG. 17 , the battery circuit maycomprise a power regulator 320 to control the power supplied by thepower savers 310 to the motor 65. The power regulator 320 may also bepart of the power pack 299, or it may be a separate component. Asmentioned above, the motor 65 may be a brushed motor. The speed ofbrushed motors generally is proportional to the applied input voltage.The power regulator 320 may provide a highly regulated output voltage tothe motor 65 so that the motor 65 will operate at a constant (orsubstantially constant) speed. According to various embodiments, thepower regulator 320 may comprise a switch-mode power converter, such asa buck-boost converter, as shown in the example of FIG. 17 . Such abuck-boost converter 320 may comprise a power switch 322, such as a FET,a rectifier 32, an inductor 326, and a capacitor 328. When the powerswitch 322 is on, the input voltage source (e.g., the power sources 310)is directly connected to the inductor 326, which stores energy in thisstate. In this state, the capacitor 328 supplies energy to the outputload (e.g., the motor 65). When the power switch 320 is in the offstate, the inductor 326 is connected to the output load (e.g., the motor65) and the capacitor 328, so energy is transferred from the inductor326 to the capacitor 328 and the load 65. A control circuit 330 maycontrol the power switch 322. The control circuit 330 may employ digitaland/or analog control loops. In addition, in other embodiments, thecontrol circuit 330 may receive control information from a mastercontroller (not shown) via a communication link, such as a serial orparallel digital data bus. The voltage set point for the output of thepower regulator 320 may be set, for example, to one-half of the opencircuit voltage, at which point the maximum power available from thesource is available.

In other embodiments, different power converter topologies may beemployed, including linear or switch-mode power converters. Otherswitch-mode topologies that may be employed include a flyback, forward,buck, boost, and SEPIC. The set point voltage for the power regulator320 could be changed depending on how many of the battery cells arebeing used to power the motor 65. Additionally, the power regulator 320could be used with the secondary accumulator devices 342 shown in FIG.13 . Further, the forward-reverse switch 316 could be incorporated intothe power regulator 320, although it is shown separately in FIG. 17 .

Batteries can typically be modeled as an ideal voltage source and asource resistance. For an ideal model, when the source and loadresistance are matched, maximum power is transferred to the load. FIG.18 shows a typical power curve for a battery. When the battery circuitis open, the voltage across the battery is high (at its open circuitvalue) and the current drawn from the battery is zero. The powerdelivered from the battery is zero also. As more current is drawn fromthe battery, the voltage across the battery decreases. The powerdelivered by the battery is the product of the current and the voltage.The power reaches its peak around at a voltage level that is less thanthe open circuit voltage. As shown in FIG. 18 , with most batterychemistries there is a sharp drop in the voltage/power at higher currentbecause of the chemistry or positive temperature coefficient (PTC), orbecause of a battery protection device.

Particularly for embodiments using a battery (or batteries) to power themotor 65 during a procedure, the control circuit 330 can monitor theoutput voltage and control the set point of the regulator 320 so thatthe battery operates on the “left” or power-increasing side of the powercurve. If the battery reaches the peak power level, the control circuit330 can change (e.g., lower) the set point of the regulator so that lesstotal power is being demanded from the battery. The motor 65 would thenslow down. In this way, the demand from the power pack would rarely ifever exceed the peak available power so that a power-starving situationduring a procedure could be avoided.

In addition, according to other embodiments, the power drawn from thebattery may be optimized in such a way that the chemical reactionswithin the battery cells would have time to recover, to thereby optimizethe current and power available from the battery. In pulsed loads,batteries typically provide more power at the beginning of the pulsethat toward the end of the pulse. This is due to several factors,including: (1) the PTC may be changing its resistance during the pulse;(2) the temperature of the battery may be changing; and (3) theelectrochemical reaction rate is changing due to electrolyte at thecathode being depleted and the rate of diffusion of the freshelectrolyte limits the reaction rate. According to various embodiments,the control circuit 330 may control the converter 320 so that it draws alower current from the battery to allow the battery to recover before itis pulsed again.

As mentioned above, according to various embodiments the battery pack299 may comprise multiple battery cells 310. FIG. 22 shows an embodimentwith six (6) battery cells 310. The battery cells 310 may be, forexample, lithium primary batteries. According to various embodiments,the battery pack 299 may have only a fraction of the battery cellsinternally connected. For example, as shown in FIG. 22 , cell 310 a isconnected to cell 310 b, cell 310 c is connected to cell 310 d, and cell310 e is connected to cell 310 f. However, cell 310 b is not connectedinternally in the battery pack to cell 310 c, and cell 310 d is notconnected internally in the battery pack to cell 310 e. The handle 6 ofthe instrument 10 in such embodiments may comprise a battery cellconnector 1300 that connects the cells 310 in series only when thebattery pack 299 is physically inserted in the instrument 10. Forexample, the connector 1300 may comprise a positive output terminal1302, a connector 1304 that series connects cell 310 b to cell 310 c, aconnector 1306 that connects cell 310 d to cell 310 e, and a negativeoutput terminal 1308.

FIG. 23 shows an embodiment of the instrument 10 where a replaceable,removable battery pack 299 is installed in the handle 6 of theinstrument 10. As shown in FIG. 23 , the battery cell connector 1300 maybe integrated into the handle 6 such that, when the battery pack 299 isinserted into the handle 6, the battery cell connector 1300 makes thenecessary battery cell connections.

Of course, in other embodiments, battery packs with a different numberof internal cells and different numbers of internally connected cellsmay be used. For example, FIG. 24 shows an embodiment with six cells 310a-f, where two sets of three cells (cells 310 a-c and cells 310 d-f) areconnected together.

The devices disclosed herein can be designed to be disposed of after asingle use, or they can be designed to be used multiple times. In eithercase, however, the device can be reconditioned for reuse after at leastone use. Reconditioning can include any combination of the steps ofdisassembly of the device, followed by cleaning or replacement ofparticular pieces, and subsequent reassembly. In particular, the devicecan be disassembled, and any number of the particular pieces or parts ofthe device can be selectively replaced or removed in any combination.Upon cleaning and/or replacement of particular parts, the device can bereassembled for subsequent use either at a reconditioning facility, orby a surgical team immediately prior to a surgical procedure. Thoseskilled in the art will appreciate that reconditioning of a device canutilize a variety of techniques for disassembly, cleaning/replacement,and reassembly. Use of such techniques, and the resulting reconditioneddevice, are all within the scope of the present application.

Preferably, the various embodiments of the invention described hereinwill be processed before surgery. First, a new or used instrument isobtained and if necessary cleaned. The instrument can then besterilized. In one sterilization technique, the instrument is placed ina closed and sealed container, such as a thermoformed plastic shellcovered with a sheet of TYVEK. The container and instrument are thenplaced in a field of radiation that can penetrate the container, such asgamma radiation, x-rays, or high-energy electrons. The radiation killsbacteria on the instrument and in the container. The sterilizedinstrument can then be stored in the sterile container. The sealedcontainer keeps the instrument sterile until it is opened in the medicalfacility.

It is preferred that the device is sterilized. This can be done by anynumber of ways known to those skilled in the art including beta or gammaradiation, ethylene oxide, steam and other methods.

While the present invention has been illustrated by description ofseveral embodiments and while the illustrative embodiments have beendescribed in considerable detail, it is not the intention of theapplicant to restrict or in any way limit the scope of the appendedclaims to such detail. Additional advantages and modifications mayreadily appear to those skilled in the art. The various embodiments ofthe present invention represent vast improvements over prior staplemethods that require the use of different sizes of staples in a singlecartridge to achieve staples that have differing formed (final) heights.

Accordingly, the present invention has been discussed in terms ofendoscopic procedures and apparatus. However, use herein of terms suchas “endoscopic” should not be construed to limit the present inventionto a surgical stapling and severing instrument for use only inconjunction with an endoscopic tube (i.e., trocar). On the contrary, itis believed that the present invention may find use in any procedurewhere access is limited, including but not limited to laparoscopicprocedures, as well as open procedures. Moreover, the unique and novelaspects of the various staple cartridge embodiments of the presentinvention may find utility when used in connection with other forms ofstapling apparatuses without departing from the spirit and scope of thepresent invention.

What is claimed is:
 1. A surgical instrument comprising: an end effectorcomprising a moveable firing driver; an electric motor for actuating thefiring driver; and a motor control circuit for controlling the motor,wherein the motor control circuit comprises: a power source connected tothe motor for electrically powering the motor; a charge accumulatordevice; and a switching circuit connected to the power source and thecharge accumulator device, wherein the switching circuit comprises: afirst switch for selectively connecting the charge accumulator device tothe power source not in series to charge the charge accumulator device;and a second switch for selectively connecting the charge accumulatordevice in series with the power source to provide additional power tothe motor, wherein, when the first switch is selectively connecting thecharge accumulator device to the power source, the second switch is notselectively connecting the charge accumulator device in series with thepower source.
 2. The surgical instrument of claim 1, wherein the chargeaccumulator device comprises a capacitor.
 3. The surgical instrument ofclaim 2, wherein the charge accumulator device comprises anultracapacitor.
 4. The surgical instrument of claim 1, wherein the powersource comprises a plurality of series connected battery cells.
 5. Thesurgical instrument of claim 4, further comprising a power sourceselection switch connected to the power source for connecting, when in afirst state, all of the battery cells to the motor, and, when in asecond state, a subset of the battery cells to the motor.
 6. Thesurgical instrument of claim 1, wherein the end effector comprises acircular-cutting end effector.
 7. The surgical instrument of claim 1,wherein the end effector comprises a linear-cutting end effector.
 8. Thesurgical instrument of claim 1, wherein the motor control circuitfurther comprises a current control circuit, connected to the powersource, for varying the current supplied to the motor from the powersource, such that the motor has at least: a first, low power operationalmode for a first portion of a firing stroke cycle of the surgicalinstrument; and a second, high power operational mode for a secondportion the firing stroke cycle of the surgical instrument.
 9. Thesurgical instrument of claim 1, wherein: the motor comprises at leasttwo windings; and the motor control circuit is for selectivelyconnecting the at least two windings in series or in parallel.
 10. Thesurgical instrument of claim 1, wherein the moveable firing drivercomprises at least one of a cutting instrument and a staple driver. 11.A surgical instrument comprising: an end effector comprising a moveablefiring driver; an electric motor for actuating the firing driver; and amotor control circuit for controlling the motor, wherein the motorcontrol circuit comprises: a power source comprising a negative terminaland a positive terminal; a charge accumulator device comprising a firstterminal and a second terminal, wherein the charge accumulator device isconfigured to be chargeable with a voltage potential across the firstand second terminals; and a switching circuit connected to the powersource and the charge accumulator device, wherein the switching circuitcomprises: a first switch that, when closed, provides a current pathfrom the positive terminal of the power source to the motor; a secondswitch that, when closed, provides a current path from the positiveterminal of the power source to the first terminal of the chargeaccumulator device; and a third switch that, when closed, provides acurrent path from the negative terminal of the power source to thesecond terminal of the charge accumulator device.
 12. The surgicalinstrument of claim 11, wherein when the first switch is closed, thesecond switch is open, and the third switch is open, the switchingcircuit powers the motor with the power source.
 13. The surgicalinstrument of claim 11, wherein when the first switch is closed, thesecond switch is open, and the third switch is closed, the switchingcircuit powers the motor with the power source and simultaneouslycharges the charge accumulator device to the voltage potential.
 14. Thesurgical instrument of claim 11, wherein when the first switch is open,the second switch is closed, and the third switch is open, the switchingcircuit connects the charge accumulator device to the power source inseries and powers the motor with the power source and the chargeaccumulator device.
 15. The surgical instrument of claim 11, wherein thecharge accumulator device comprises a capacitor.
 16. The surgicalinstrument of claim 15, wherein the charge accumulator device comprisesan ultracapacitor.
 17. The surgical instrument of claim 11, wherein themoveable firing driver comprises at least one of a cutting instrumentand a staple driver.
 18. A surgical instrument comprising: an endeffector comprising a moveable firing driver; an electric motor foractuating the firing driver; a motor control circuit for controlling themotor, wherein the motor control circuit comprises: a power source; acharge accumulator device; and control means for: in a first instance,connecting the electric motor to the power source for powering the motorwith the power source; in a second instance, connecting the electricmotor to the power source for powering the motor with the power sourceand simultaneously connecting the charge accumulator device to the powersource not in series with the motor for charging the charge accumulatordevice; and in a third instance, connecting the charge accumulatordevice to the power source in series for powering the electric motorwith the power source and the charge accumulator device.
 19. Thesurgical instrument of claim 18, wherein the moveable firing drivercomprises at least one of a cutting instrument and a staple driver. 20.The surgical instrument of claim 18, wherein the charge accumulatordevice comprises at least one of a capacitor and an ultracapacitor.